Dietary reference values for calcium and vitamin D

In the UK, recommendations for energy and nutrition requirements are called Dietary Reference Values (DRVs). DRVs are not recommendations for individuals, but for groups of healthy people in the UK population.

Reference Intakes

Reference intakes (RIs) are special guidelines used to provide clear and consistent information on labels for packaged foods. They are a guide on approximate amounts of energy and nutrients required on a daily basis for a healthy balanced diet. RI values are based on an average-sized woman doing an average amount of physical activity. Individual needs may be different and will depend on age, gender and physical activity.

The table below shows RIs for energy, fats, carbohydrates, protein and salt in the UK.

There are four other useful values that can be defined as follows:

1. Estimated Average Requirement (EAR)
   This is an estimate of the average requirement of energy or a nutrient. Half of the group of people it applies to will need more than this value, and half of the group will need less than this.

2. Reference Nutrient Intake (RNI)
   This is the amount of nutrient that is enough to ensure that nearly all (97.5%) of the group of people it applies to will be getting enough.

3. Lower Reference Nutrient Intake (LRNI)
   This is the amount of a nutrient that is enough only for a very small proportion (2.5%) of the group of people it applies to.

4. Safe Intake
   This value is used when there is not enough data or evidence to be able to set an EAR, RNI or LRNI.

EAR is used particularly for energy requirements. For most vitamins and minerals, DRVs are provided only as RNIs. In general, intakes below the LRNI are almost certainly not enough for most people.

Dietary reference values for calcium

The table below shows the Reference Nutrient Intake (RNI) for calcium for different groups of the population, split into groups by age for children up to 10 years and by gender and age from 11 years upwards.

Calcium RNI (mg/day)

Dietary reference values for Vitamin D

In 1991, an RNI for vitamin D was set only for population groups that were thought to be at high risk of deficiency, for example, people who have low sun exposure or who are over 65. Vitamin D deficiency is defined in the UK as a serum (i.e blood) concentration of vitamin D that is less than 25 nmol/L, while vitamin D sufficiency is defined as a concentration of 50 nmol/L or above.

Based on the best previous evidence, it was assumed that, for most people, the amount of vitamin D produced by safe exposure to sunlight in the summer months would be sufficient to make enough vitamin D to keep the concentration above 25 nmol/L during winter. It is now known that this is not the case.

A fresh review of all the current evidence was conducted by the Scientific Advisory Committee on Nutrition (SACN) to see if the recommendations set in 1991 were still appropriate, using musculoskeletal health as the basis for setting DRVs for vitamin D.

The evidence overall suggested that risk of poor musculoskeletal health increases at vitamin D concentrations below 25 nmol/L. A vitamin D concentration of 25 nmol/L or more was therefore considered to be a ‘population protective level’, i.e. the concentration that 97.5% of individuals in the UK should achieve, or be above, for protecting musculoskeletal health. Only an RNI was established because this ‘protective level’ approach did not allow for an Estimated Average Requirement (EAR) or Lower Reference Nutrient Intake (LRNI).

In a change to the previous advice, SACN is now recommending:

• An RNI of 10 micrograms of vitamin D per day, throughout the year, for everyone in the general population aged 4 years and older.
• An RNI of 10 micrograms of vitamin D per day for pregnant and lactating women and population groups at increased risk of vitamin D deficiency.
• A ‘safe intake’ of 8.5 to 10 micrograms per day for all infants from birth to 1 year of age.
• A ‘safe intake’ of 10 micrograms per day for children aged 1 to 4 years.

Public Health England have now issued new recommendations to the public, based on the findings of the SACN review.

Some key points are:

• The majority of the UK will have sufficient vitamin D intakes during the spring and summer through safe sunlight exposure on the skin combined with the vitamin D consumed within a healthy, balanced diet

• During autumn and winter, it is difficult for people to meet the 10 micrograms per day vitamin D recommendation just by consuming foods naturally containing or fortified with vitamin D. It is therefore recommended that individuals consider taking a daily supplement of 10 micrograms of vitamin D during the autumn and winter months

• People whose skin has little or no exposure to the sun are at increased risk of vitamin D deficiency and therefore need a vitamin D supplement throughout the year

• Minority ethnic groups with dark skin may also not get enough vitamin D from sunlight in the summer and therefore should consider taking a daily supplement all year round

• Babies who have more than about a pint of infant formula do not need to be supplemented with vitamin D because formulas are already fortified. The Department of Health recommends that babies are exclusively breastfed until around six months of age, and breastfed babies from birth to one year should be given a daily supplement containing 8.5-10 micrograms of vitamin D so that they get enough.

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